Method of manufacturing blind rivet

ABSTRACT

A method of manufacturing blind rivets is revealed. First cutting a steel wire rod to get a rod with required length and forming a head portion at one end of the rod. Then performing threading on an outer surface of the rod to form outer threads and carrying out heat treatment including quenching and tempering at 380° C.±50° C. to get a threaded rod. Next cutting a steel wire rod according to a length required to get a tube and forming a through hole axially penetrating the tube and corresponding to the threaded rod. Then forming a mounting portion at an outer edge of one end of the tube, carrying out optical heat treatment at 1100° C.±100° C., and performing electroplating to get an outer tube. Lastly the threaded rod is inserted into the through hole of the outer tube and the assembly is completed.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method of manufacturing rivets,especially to a method of manufacturing blind rivets by which the blindrivet manufactured provides excellent support strength during rivetingand fixation of workpieces for secure and reliable fastening of theworkpieces. Thereby the workpieces are securely fastened without easyloosening and the blind rivet is more convenient to use.

Description of Related Art

For permanent connection of workpieces such as sheet metal, mechanicalstructure, etc., blind rivets are used. Once the workpieces are fixed bythe blind rivet, they are hard to separate from each other.

A blind rivet mainly includes a sleeve, a mounting flange projectingfrom one end of the sleeve, and a mandrel inserted through the sleeveand provided with an against portion on one end thereof. Thus themandrel is abutting against an outer side of one end of the sleeve,opposite to the end of the sleeve with the flange by the againstportion. While in use, insert the sleeve into a mating hole formed inworkpieces and then the mounting flange is abutting against one end ofthe mating hole. Then the mandrel is pulled by a hand tool so that theagainst portion of the mandrel presses the sleeve toward the mountingflange. Thus the workpieces are clamped and fastened between a deformedpart of the sleeve caused by squeezing of the against portion of themandrel and the mounting flange. At the same time, the mandrel is drawnby the hand tool and broken. Thereby the fastening is complete.

Although the blind rivet mentioned above shows expected results, theabove blind rivet provides limited support strength after the workpiecesbeing riveted by the blind rivet and the workpieces still get loose.This cause inconvenience in use.

Thus there is room for improvement and there is a need to provide amethod of manufacturing blind rivets, which address issues of rivetsproduced by the methods available now.

SUMMARY OF THE INVENTION

Therefore, it is a primary object of the present invention to provide amethod of manufacturing blind rivets by which the blind rivetmanufactured provides excellent support strength during riveting andfixation of workpiece for secure and reliable fastening of theworkpiece. Thereby the workpiece is tightly fastened without easyloosening and the blind rivet is more convenient to use.

In order to achieve the above object, a method of manufacturing blindrivets according to the present invention includes the following stepswhile the blind rivet manufactured includes a threaded rod and an outertube.

First cut a steel wire rod according to a length required to get a rodand form a head portion at one end of the rod. Then perform threading onan outer surface of the rod to form outer threads and carry out heattreatment including quenching and tempering at 380° C.±50° C. to get thethreaded rod.

Next cut a steel wire rod according to a length required to get a tubeand form a through hole axially penetrating the tube and correspondingto the threaded rod. Then form a mounting portion at an outer edge ofone end of the tube, carry out optical heat treatment at 1100° C.±100°C. with a moveable heat source, and perform electroplating to get theouter tube.

Lastly, the threaded rod is inserted into the through hole of the outertube and the head portion of the threaded rod is exposed outside andabutting against an end of the outer tube opposite to the end of theouter tube with the mounting portion.

A protruding locking portion which is corresponding to the mountingportion is formed on an inner surface of the through hole of the outertube.

The optical heat treatment carried out on the outer tube is laser heattreatment.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein:

FIG. 1 is a block diagram of a manufacturing process of an embodimentaccording to the present invention;

FIG. 2 is a schematic drawing showing an embodiment in use according tothe present invention;

FIG. 3 is another schematic drawing showing a rivet manufactured by anembodiment in use according to the present invention;

FIG. 4 is a further schematic drawing showing a rivet manufactured by anembodiment in use according to the present invention;

FIG. 5 is a further schematic drawing showing a rivet manufactured by anembodiment in use according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to learn technical content, purposes and functions of thepresent invention more clearly and completely, please refer to thefollowing detailed descriptions, figures and reference signs.

Refer to FIG. 1 and FIG. 2 , a blind rivet produced by the presentmethod mainly includes a threaded rod 1 and an outer tube 2. A method ofmanufacturing blind rivets includes the following steps.

First cut a steel wire rod according to a length required to get a rodand form a head portion 11 at one end of the rod. Then perform threadingon an outer surface of the rod to form outer threads 12, and carry outheat treatment including quenching and tempering at 380° C.±50° C. toget the threaded rod 1.

In the beginning, cut a steel wire rod according to a length required toget a tube and form a through hole 21 which is axially penetrating (acenter/central axis of) the tube and corresponding to the threaded rod1. Then form a mounting portion 22 at an outer edge of one end of thetube and a protruding locking portion 23 on an inner surface of thethrough hole 21 of the tube while the protruding locking portion 23 iscorresponding to the mounting portion 22. Next carry out optical heattreatment such as laser heat treatment at 1100° C.±100° C. with amoveable heat source and then perform electroplating to get the outertube 2.

While in use, the threaded rod 1 is inserted into the through hole 21 ofthe outer tube 2 and the head portion 11 of the threaded rod 1 isexposed outside and abutting against an end of the outer tube 2 oppositeto the end of the outer tube 2 with the mounting portion 22. Then theouter tube 2 is inserted through a fixing hole 31 formed in workpiece 3and the mounting portion 22 is abutting against an outer side at one endof the fixing hole 31, as shown in FIG. 2 . A rivet tool 4 is used topull the threaded rod 1 so that the head portion 11 of the threaded rod1 presses the outer tube 2 toward the mounting portion 22, as shown inFIG. 3 . The protruding locking portion 23 which is located on an innersurface of the through hole 21 of the outer tube 2 and corresponding tothe mounting portion 22 is also locked and fixed on a periphery of thethreaded rod 1. Along with squeezing and deformation of the outer tube 2caused by the head portion 11, a deformed part of the outer tube 2 isalso abutting against the workpiece 3, as shown in FIG. 4 . Lastly thethreaded rod 1 is broken due to pulling of the rivet tool 4 and theworkpiece 3 is clamped and fixed between the mounting portion 22 and thedeformed part of the outer tube 2 caused by squeezing of the headportion 11 of the threaded rod 1. At the same time, the threaded rod 1is also locked and fixed by the protruding locking portion 23 in thethrough hole 21 of the outer tube 2, without coming off, as shown inFIG. 5 .

Under the same specification, the blind rivet produced by the presentmethod has much higher tensile strength than the blind rivet availablenow so that the blind rivet manufactured by the present method is moreconvenient to use.

In summary, the blind rivet produced by the present method providesexcellent support strength during riveting and fixation of the workpiecefor secure and reliable fastening of the workpiece. Thereby theworkpiece is securely fastened without easy loosening and the blindrivet is more convenient to use.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, and representative devices shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalent.

What is claimed is:
 1. A method of manufacturing a blind rivet whichincludes a threaded rod and an outer tube comprising the steps of:cutting a steel wire rod according to a length required to get a rod andforming a head portion at one end of the rod; then performing threadingon an outer surface of the rod to form outer threads and carrying outheat treatment including quenching and tempering at 380° C.±50° C. toget the threaded rod; cutting a steel wire rod according to a lengthrequired to get a tube and forming a through hole axially penetratingthe tube and corresponding to the threaded rod; next forming a mountingportion at an outer edge of one end of the tube, carrying out opticalheat treatment at 1100° C.±100° C. with a moveable heat source, andperforming electroplating to get the outer tube; and inserting thethreaded rod into the through hole of the outer tube and the headportion of the threaded rod exposed outside and abutting against an endof the outer tube arranged opposite to the end of the outer tube withthe mounting portion to complete assembly of the blind rivet.
 2. Themethod as claimed in claim 1, wherein a protruding locking portion whichis corresponding to the mounting portion is formed in the through holeof the outer tube.
 3. The method as claimed in claim 1, wherein theoptical heat treatment carried out on the outer tube is laser heattreatment.